Common rose to fame as a rapper in the 1990s, and his childhood and teenage years clearly influenced his music. He’s also found success as an actor, and now as a writer – his  new memoir, “One Day It’ll All Make Sense,” which shares the title of his 1997 album, came out yesterday. Common and his mother,  Dr. Mahalia Hines, discuss the book, the impact of racism and the death of Emmett Til on Common’s music, and why he went into rap.